Thanks! Just to clarify, we're not actually in San Diego but are under "San Diego Gas & Electric" :) SD temps tend to be a bit warmer than where we are. We're about an hour to hour and a half north of SD. What I've been having trouble with is finding a contractor who is open and willing to doing a manual J. I hear some have better luck after you've committed to and chosen a contractor but it seems most of them just don't want to do it or write it off! I've only had ONE contractor do a "Manual J" but again it was online sight unseen. I'm not sure if he was just using loadcalc and got the details about my place after getting my address but he told me that I could do a 4ton system and would be at the "upper end" whereas 5ton would be more comfortable. It doesn't seem to make much sense to me to step-up to 5ton if we have a 4ton system in place though if the existing system has been doing its job sufficiently (again, hard to know for sure as we haven't been here for that long and haven't run either system a ton... now that the furnace is out, it's kind of a moot point).

The other thing we have been considering is installing a whole house fan and gable exhaust fan. I've heard mixed things about whole house fans and if the attic doesn't get that hot, a gable exhaust fan may not be worth while. Maybe we can wait on those but I hear those can help a lot.

BTW: in terms of pricing, most of the quotes I've gathered so far are closer to $10k on the lower efficiency/single stage side and get up to $15k-16k and upwards depending on brand/efficiency. Does this sound about right for pricing today and in Southern CA?

Hi, jplee3,

My understanding is that Title 24 regulations require you to have a HERS rater verify your HVAC system after installation. A HERS rater should also be able to help you make an informed choice about the best HVAC equipment for your climate and your personal needs. Here's a link to additional information:

https://www.cheers.org/articles/mandatory-hers-requirement-where-do-i-start/#:~:text=A%20HERS%20test%20is%20required,more%20feet%20of%20duct%20work.

"BTW: in terms of pricing, most of the quotes I've gathered so far are closer to $10k on the lower efficiency/single stage side and get up to $15k-16k and upwards depending on brand/efficiency. Does this sound about right for pricing today and in Southern CA?"

Now is a bad time to pay for semi-skilled labor. Unless you're desperate, wait a year or so, until prices come down!

Do you think prices will actually go down given supply chain issues + inflation?

I'll share my own experience for a house I own less than one hour away but a bit closer to the beach than Laguna Hills. Short distances can make a difference, as you know. The work was done not quite 3 years ago.

I have a freestanding home of about 1450 interior sq feet that was built as one home of a development of 175 units in the late 1990s. Single paned windows, poor wall insulation (interior walls get HOT on the west side on summer afternoons). I'm an SDGE customer for gas and electricity.

The house was built with a 60K BTU (gross) 80% gas furnace and a 3 ton AC unit. We had an honest load calculation done as part of the successful bid that we chose and the heat load was calculated to be about 35KBTU net (which can be supplied by an 80% 45K BTU furnace) and the cooling load at 25K BTU which suggests a 2 ton AC system. Original equipment installed under the aegis of a builder is always oversized as ours was - 60K gross furnace could be replaced by 45K, 3 ton AC replaced by 2 tons. The replacement HVAC contractor said either 2 or 2.5 tons of AC would be fine with him, my choice, and I chose 2 tons. It's a very temperate area, as you know, and not a lot of horsepower should be needed for either heating or cooling

Before replacement, whether heating or cooling, cycles were typically short and frequent. Ten-minute blasts of hot air or cold air, off for ten minutes, back on again. I'm not too far from the water and it can get a bit humid some days. The old system never stayed on long enough to reduce the indoor humidity much, the new one does, and the temps from room to room were very uneven. The new heating and cooling systems work well and provide more comfort and more economical operation.

Get the right size. Getting more than the calcs show is a minus, not a plus. A two-stage system can overcome being too far oversized but the small indoor/outdoor temperature differences for most of the year and usually dry summers hardly justify the extra expense. I'd say the same for a gas furnace - our heating season isn't very long and I don't think the higher efficiency models are worthwhile. As for furnace vs heat pump, without solar on the roof, I'd stick to a gas furnace, which was what I decided to do for my place.

Thanks Elmer! Mind sharing who your HVAC contractor is? Its very difficult finding a contractor willing to do the manual J at the moment... Most want to just upsell the larger systems

I took a look at the website and their service area pretty much stops at Oceanside. My place is about 25 minutes down the 5 from there so more in the heart of his territory. You could be 40 minutes or so too far north of the northern edge of his territory. Back a few years, he was very busy and I had to wait 6 weeks for a scheduled time. How things are now with as crazy as the market is I can only imagine. .

I'm sure you'll find someone. Be upfront about your expectations. I had one bidder say that if I accepted their bid the week it was delivered, they would give me a $1000 credit to take a cruise to Mexico. I had trouble not laughing at that but I did smile. There are honest and capable operators out there, you'll find one. The springtime is a good time to get work scheduled, neither heating nor cooling peak period. Good luck.

Edit to add - CR Homes' comment above is correct. One element of the rules, enforced as part of the building permit, is that once the work is done, an independent HERS test of duct leakage needs to be performed. My contractor arranged this to be done. If the required max leakage standard isn't met, it's my understanding that the contractor needs to attempt to better seal accessible connections and duct segments. Then a retest is done.

A conscientious HVAC contractor will insure all joints and plenum connections are properly sealed as part of the job in the first place. And will inspect ducts for condition. My system, though 20 years old and with a number of flex duct runs, passed with a lot of room to spare.

Don't let a sloppy contractor suggest you can save money by not getting a permit. It will add to the cost but it's your best means to be sure the work is properly done. Also, in California, a seller of property needs to disclose if any work was done that while needing a permit, was done without one. You don't want to have to disclose that.

What are your guys' thoughts on zoning? I had a contractor come out today and threw it out as an option where he would relocate the furnace in the attic, zone it, and re-duct everything. We haven't been here a full summer yet but I want to say the place stays relatively cool. Zoning seems like it might be a bit overkill. He was pitching Carrier stuff hard as he exclusively installs their stuff. I haven't received the bid yet but it sounds like it's going to be quite expensive.

I asked him about load calcs and he actually was saying that he has done many of them and knows how to do them etc. But, he said that he firmly believes that based on his experience with doing so many of those and for our house, we likely don't need it and was suggesting that while we could probably get away with a 3-3.5ton system, he'd recommend just going up to a 4ton also to account for climate change and temps rising year over year for the next decade or two just to be safe. At least he wasn't the first to completely shun load calcs though...

We'll throw in some load calcs but then add to that to account for climate change?

Just so you know a load calc is a calculation based around the hottest average temperature at your location. But a contractor who is then going to add in for climate change?

That's no different from someone not doing a load calc and then putting in whatever size they think.

In many current situations due to equipment selection they don't make 1/2 ton increments in certain equipment.

So the mentality of those who know? Lets perform a heat load calc to calculate for the hottest 2 or 3 weeks of the year to size an air conditioner "properly" then that heat load tells us we need 3.20 tons. The equipment we've chosen don't make 3.5 tons, so we go to 4 tons to be over sized more than 90% of the time. The purpose of the heat load calc again? To be wrong 90% of the time. Does that make sense? Heat loads are tools in the hands of those who know how to use them.

That 90% over sized rate is if we get the calculation right and or don't account for climate change. LOL. Ha, ha, ha.

Inflation issues for California? Only going to get worse in 2023 no more R410a installations out there in la la land, unless someone sues and wins out there. Yeah so anything you buy now is likely to be cheaper but obsolete. Better hope you don't spring any refrigerant leaks.

To make matters worse, the new refrigerant choices coming out are mildly flammable. What goes good with burning forest fires? Yeah you can't make this kind of logic up.

How flammable? mildly. Now everyone in unison say "how dare you!" ha, ha, ha.

lol, thanks for the input. Yea, every response I've still gotten thus far from all contractors out is "yes, I've done load calcs before. No you don't need one. What you need is a 4 or 5 ton. Trust me. I know what I'm doing" - I'm scratching my head here as to *what* the disconnect is... is it just a Southern California thing? I can't even get a straight answer as to why there's such a drastic difference of opinion when it comes to load calcs to begin with! Anyway, if I go with this guy, I think I could probably demand a load calc and sizing the equipment and he would be open to doing it. I just think it's strange that no contractor thus far has suggested doing a load calc up front as a condition to sizing the system. Half of them have said it's unnecessary because we live in such a mild climate so you don't need to worry about oversizing - a 5ton system won't short cycle in your house and if you put anything smaller it'll take *forever* to cool, etc.... that's the main logic and justification right now for those pushing a 5ton system. So I'm really not sure what's missing between loadcalc.net and what they're saying.

I heard about what happened with R22 so figure it won't be too different with R410a lol. I'm sure CA will start jacking up the prices of natural gas too, to create attrition of gas furnace usage.

As a rabbit hole discussion - CARB has been trying to push some BS requirements for the sportfishing industry out here (and I love fishing) that requires new engines in all recreational sport boats because the emissions are way too high. There's probably a fleet of less than 100 operational and recreational sport boats in all of CA and maybe no more than several dozen of them out on a water at a given time not operating on full throttle the entire time. The new engines they want them to put in the boats run so hot that if they installed them, they would pose a fire danger and safety risk because uhhh pretty much all these boats are made of one or two things: fiberglass and wood. Both of those don't really go well with...high heat? lol. Even then, the cost of the engines and an overhaul like that would end up putting these guys out of business. These aren't the evil corporations btw - they're mostly family-owned small businesses. People sure seem to have a lot of great ideas but never think much about those ideas beyond how great they are.

Free on line load calculators can be very inaccurate. If you want to do your own load calculation then invest $49 into HVAC Calc.

Given what I have read so far, a 3 ton AC is probably the right size. A 3.5 ton or 4 ton if is a 2-stage system would not be out of the question. The contractors who want to install a 5 ton system with your 4 ton duct work either don't know what they are doing or don't care about the problems this will cause.

A 14 SEER system is fine for your mild summer climate. The issue is 14 SEER is the minimum allowed in the Southern US. These tend to be low end equipment. I would recommend staying away of the low end of any manufacturer's line up.

A 80% efficiency gas furnace would also be fine. Again these are the lowest efficiency allowed and in some areas the choices are limited. If you post your gas and electric rates a calculation can be done to compare the relative costs of heating with the gas furnace and a heat pump.

Thanks mike_home. The guys at hvac-talk turned me to loadcalc.net so that's primarily what I've been looking at and what they've made suggestions based off of. So you're saying loadcalc.net isn't very accurate? I thought it was more a "garbage in garbage out" kind of thing, regardless of the calc. Is there something that HVAC Calc does that the others (including loadcalc.net) don't do?

Someone was saying that if we do upsize, consider getting a 2-stage or variable speed so you can at least have the option to operate at a lower speed. Otherwise, single stage low efficiency presumably 3ton matched with a 60-80k btu furnace is more than likely good enough.

What you said about the low end equipment and typically 14 SEER only existing in those lines echoes what the last contractor out said, or he was generally advising the same thing: Carrier and Bryant 15seer or higher and Payne 14SEER - Payne might be OK for rentals but don't do it for your primary residence. Now that I think about it, why would I want the lowest end equipment in a rental too? This potentially means more service calls lol. We don't have a rental so I don't have to worry about that though hahaha. I was looking at http://www.hvacopcost.com/ - is that what you're referring to?

SDGE electric rates range from 39-49cents now and I expect these to keep going up (they've been receiving a number of complaints but they're a monopoly and have a chokehold over all of San Diego County and South OC where I'm located, unfortunately. The *other* monopoly, SoCal Edison, has lower rates but SDGE blames higher rates on a smaller overall customer base. They have no explanation for the rapidly increasing electric costs however.

Anyway, gas is anywhere from $1.50-$2~ very roughly per therm. It's definitely less expensive to run gas out here but everyone is saying natural gas prices will be hiked up especially as CA tries to wean people off of it and towards electric.

So right now we are considering going solar since we have update our electric panel anyway. And the topic of heatpumps is a discussion point. The last contractor who came out actually was suggesting the option of going hybrid, which every other contractor has shunned. He said, with full out confidence, that the heatpump + gas furnace install will qualify for the $3k rebate incentive. Every other contractor I've asked about this either doesn't know or they say that a gas furnace is not allowed and it has to strictly be a full-on heatpump w/ air handler install (and with picture proof). So who knows... anyway, I'm pricing things out right now and just researching. We are currently without heat but have sort of learned to deal with it. I'm kind of wondering if we'll be able to hold out until summer to see how hot it really gets. Plus, if we're thinking about solar/heat-pump then it might make more sense just to try to hold out while researching solar panels/installs, etc.

BTW: If I did decide to zone and relocate, it would add $7300 to the overall cost. $3k to zone, $2k to relocate, and $2300 to install new ducting. I've heard some contractor tell me zoning is kind of pointless for our place and not necessary. I would lean towards doing it if we had drastic problems with imbalances in heating/cooling but I don't have a good feel on things yet. We've only been in the house since October and haven't experienced a consistent "summer heat" yet. All I know is that when it's cold outside it seems to get cold inside pretty fast. Part of this could just be because we have some small portions of walls opened up and the insulation removed which I'm sure is leaking cold air in. On the flipside, when it does get warm outside, it tends to still stay cool inside the house. Upstairs it can get warmer but not super unbearable. I've had to turn on the cooling a couple times when it gets a touch warm but not for that long. This all might be a different story when summer comes, so I'm just wondering how much we'll be able to hold out.

Is there something that HVAC Calc does that the others (including loadcalc.net) don't do?

I have never used loadcalc.net. It seems you can enter data as you would Manual J software calculator. I just don't know how accurate it will be.

Don't buy an over sized 2-stage furnace or AC so then you operate it in the low stage. That is a waste of money in my opinion. On one hand you live in a mild climate so you don't need the highest efficiency equipment, but on the other hand your electric and gas rates are much higher than the current national averages.

I am not sure what the current thinking is on gas furnaces in California. Some cities are starting to ban natural gas for new how home builds. Would keeping the gas furnace make your home more attractive or less attractive to a buyer in the future?

I shudder at the thought of covering a Spanish clay tile roof with solar panels.

jplee, ask the HVAC contractors you've spoken to if they're planning on getting a permit for the equipment replacement work and, if so, you can say "Isn't a load calculation required for the permit?" I believe the answer is yes.

As far as I know, gas heating appliances have not yet been banned by the state of California. There is talk at an advanced stage about requiring heat pumps for new construction and for major remodeling jobs but not for equipment replacement. Some cities and counties have put in place such rules in advance of anything being done statewide. So far.

A lot of guys at hvac-talk swear by loadcalc.net, so it seems like it's pretty accurate AFAIK.

I had one more contractor out today who actually had "load calculation" software on his tablet where he punched in numbers, orientation of windows, doors, insulation type, ducting size, etc and he derived 3ton from that and was suggesting it strongly. In fact, he was also pushing heatpumps, not even offering gas furnace. I guess American Standard makes a 110v air handler which he said will reduce electricity usage. And he claimed that these newer heat pumps are far more efficient and won't cost nearly as much as running a gas furnace or if not now then soon - he was pushing CA's clean air initiatives and how they are eventually going to weed out natural gas usage. Anyway, his quotes are mid to mid-high per all the quotes I've gotten and he and the company he's at are one of the few that's ACCA and NCI certified. So they firmly believe in sizing correctly and not oversizing. 3ton corresponds with what someone at hvac-talk ran (he's prob the one guy on that forum who single-handedly runs the most 'blind' manual Js for ppl like me, so I'm thinking he has a pretty good feel on what would work and what is too much haha). Anyway, the contractor today didn't see the point in a 2-stage. He was pushing variable speed like crazy and was saying you might as well go all (variable) or none (single speed) if you're going to do it. His reasoning for variable speed in a moderate climate is that you can operate the unit according to the temps outside, and if they're moderate the unit won't have to work as hard and therefore would consume less electricity and likely last longer. Versus a single-speed unit where it's on/off and when it's on it's always on at the same high speed (he used the analogy of running the AC in your card - most of the time, at least out here, it doesn't make sense to blast your AC 100% of the time. You blast it initially then turn it down. But why would you ever want to blast it and then turn it off completely if it's hot/warm out? You'd blast it, turn it off, then start sweating 5 minutes later.

In our county, they're requiring ultra low nox units, which this contractor was saying has been a nightmare for him to deal with. They are loud but also there have been reports of them overheating and melting coils and other components of the furnace/evaporator coil. For these reasons alone, he avoids selling them completely and that was also part of his reasoning behind pushing heat pumps. Anyway, he felt a bit high pressure at the end and told me the pricing expires/is subject to change 10 days from now but that he can potentially give me an 'incentive' amount off if I can be flexible... of course, he said that incentive amount depends on the size of the job lol :T

Because CA wanting to push gas furnaces out the door, it seems like having a heat pump would be more attractive. Then again, we're not intending or looking to sell this place anytime soon. We were hoping this would be a place where we raise our kids (6 and 5).

I don't like the idea of it either but I feel like, even indirectly, CA/SDGE is slowly putting a chokehold around and punishing those who don't have or go solar... even if we do go solar, it'll still hurt but not as much as not having it later down the road. I honestly don't see it as having much of a choice... I just don't know if solar installs will ever get to a point where they're less expensive than they are now. If I had to guess, I seriously doubt any of this will get cheaper.

Elmer, I have been asking contractors as of late about permitting. I think HERs testing is required and after the job is done but I don't think I saw that load calcs/manual Js are *required* - if they are, it seems contractors 'define' what that means for themselves and/or check a checkbox to say it was done hahaha.

You're right about new construction and heat pumps. They are requiring them in that context. Some contractors believe they'll hike the natural gas prices up and eventually ban sale of NG appliances. Other contractors I've talked to think that's all BS and it will never happen, or if it does not for a very long time. Both could be partially right (in that it will happen and that it will take a very long time).

Go to this link, click on "Click here for Full documents" and a PDF will download. Go to section 4.2.1.3 and 4.3.1.4.

Title 24 info

Load calcs are very easy to force an answer out of the software. Thjey decide what result they want and then play with the inputs until that result pops up. I think the contractors suggesting they "have experience with sizing" are blowing smoke to get you to spend for more than you need and then perhaps submit a calc they've tinkered with to justify the result they've sold the customer. Many are also willing to work without getting permits so on those jobs, no load requirement would ever be done for those projects.

I think all air handlers are 110v. In my system, the furnace blower doubles as the fan for the AC (of course) and it simply plugs into the wall. I think the blower motor, all of which sold are ECM these days, is something around 300-400 watts at 110 volts, so not a big user of electricity. It's just a motor, the rest of an air handler or an AC coil (in a system with a gas furnace as I have) are passive and use no electricity.

The guy you're describing seems like a better choice than the others for having done a reasonable load calc but still with a bit of baloney in his presentation. Based on what you say, I personally might think about 3.5 or 4 tons to have a little buffer but I'm just another homeowner like you, not an expert. It can get hot where you are, you don't want to come up too short. See if he has something at 3.5. I personally never choose the lowest bidder and like to aim for the middle.

The guy I used at my place south of where you are had the software on an Ipad. He walked around with a laser measuring device, did a rough sketch with dimensions of each room and its windows and was done in about 25 minutes. The result was "3 tons to 4 tons, your choice". I asked if 3 tons was too small, and he said "No". I went for that and it seems to have been the right choice. The bonus is long runs that do a great job of dehumidifying (I'm not far from the beach).

Your home is a bit bigger than mine, and a bit older (questioning insulation) so I might go with 3.5-4. Not more.

Good luck.

Thanks Elmer. 3.5 sounds reasonable too. Ugh, so the guy who came out today left his flashlight here, which means he has to come back to get it...which means he's probably going to try to pressure me to go with him :T hahahaha

Good to know on the blow. I might be forgetting but I could have sworn the Trane XL80 unit at our condo was a different kind of plug but it was probably a standard 110v upside down lol.

Wait a sec, in your original post you said you had a 2ton system installed. Are you talking about a different house now?

"The house was built with a 60K BTU (gross) 80% gas furnace and a 3 ton AC unit. We had an honest load calculation done as part of the successful bid that we chose and the heat load was calculated to be about 35KBTU net (which can be supplied by an 80% 45K BTU furnace) and the cooling load at 25K BTU which suggests a 2 ton AC system. Original equipment installed under the aegis of a builder is always oversized as ours was - 60K gross furnace could be replaced by 45K, 3 ton AC replaced by 2 tons. The replacement HVAC contractor said either 2 or 2.5 tons of AC would be fine with him, my choice, and I chose 2 tons. It's a very temperate area, as you know, and not a lot of horsepower should be needed for either heating or cooling"

Yes, sorry, I had it right the first time, what I said and you quoted was correct for SoCal. I do believe the 110V is standard for furnaces and blowers with just fan motors. I know my two furnaces where I am both plug into standard wall sockets. Both are Bryant and besides the blower, there's a glow element to ignite the gas at startup. I don't know how many watts it is but it can't be much, it's pretty small.

I was confusing the numbers with my primary residence in the Bay Area that's larger that I had similar work done at about the same time. Both had significant equipment downsizes based on load calcs. Here, I replaced heat 105K BTU output/5 tons cool and the second system 75K BTU heat output and 3 tons cool with heat 90k BTU output/4 tons cool and second with 48 BTU heat output/2 tons cool. Each of 3 systems - 2 north, 1 south, was significantly oversized. In both homes, With hindsight the second AC in the north perhaps could have been downsized to 1.5 tons from 3 but it's fine. The new equipment provides indoor comfort for both locations on both the hottest and coldest days in houses that are old-ish and neither well sealed or insulated. Long runs so well distributed conditioned air without short hot or cold blasts.

Sorry for any confusion.

No problem - thanks Elmer! Were any of your installs attic installs by chance? Or did you relocate any of them from the garage or closet up into the attic? Right now I'm deliberating whether or not I should consider doing that or if it's really worth the additional cost (at a minmium it's $4300 and goes up from there depending on the contractor - this includes new ductwork though too).

In SoCal house, built by a developer, the furnaces for some units in the development have equipment in the garage, some are in the attic. Mine is in the attic and with flex duct in attic and hard duct down the walls. I wouldn't pay to relocate it. Garage or indoor (closet) locations are superior. Attics get very hot in the summer and what an awful place to put the blower and ducts for AC work. But for me, they're there and so be it.

In my NorCal house, the larger furnace (and AC coil) are in the garage, the smaller one is in an interior (properly vented) closet. Both have hard metal ducts that I paid to have resealed and reinsulated.

Both places passed HERS testing.

Yea, I can see how the heat wouldn't be good. All our ductwork is in the attic though so I can see why the contractors were suggesting putting the furnace up there. Logically to me it makes sense because the air delivery source would be closer to the upstairs rooms and thus the ducts wouldn't need to be as long so you'd theoretically get better airflow upstairs, which I would think is better for cooling things off where it's most needed. But yes, being in the attic there's the concern of heat, which makes me wonder about the gable exhaust fans and if those would actually alleviate much of that concern (although, some have talked about the potential of creating negative air pressure and adversely impacting your system this way... I don't know enough of the science behind it all).

Half of them have said it's unnecessary because we live in such a mild climate so you don't need to worry about oversizing - a 5ton system won't short cycle in your house and if you put anything smaller it'll take *forever* to cool, etc....

Kind of true. Mild climates have less heat, less time at that heat. To short cycle you have to have the heat infiltrating to cause the cycle. To say a 5 ton won't short cycle vs a 3 ton or 2 ton whatever, it's the same in terms of short cycle or no short cycle.

Just because the capacity of the system is whatever doesn't determine the amount of short cycling. Look at this this way -- run of the mill air conditioner needs a good 20-30 min of run time to reach the most efficient mode of operating. If the unit cycles off before that time that would be considered a short cycle.

For milder climates would you really notice this? probably not. That said if you're in a mild climate do you really need to spend more money on size & more capacity? probably not. It's going to take forever to cool? Time. If you're in a mild climate the time spent at elevated temp is short. What happens at night? The largest heat load known to man disappears until the next day, well unless you're in Alaska some where and the sun is shining close to 24/7 in some odd form of insanity. (But in Alaska how much do you hear about the need for AC? so it's all relative.)

So if you're in such a mild climate and you don't need to worry about oversizing... undersizing is probably nothing to worry about either. Sizing is like forecasting the weather. It's an occupation you can be wrong 90% of the time and still be right.

Carrier and Bryant 15seer or higher and Payne 14SEER - Payne might be OK for rentals but don't do it for your primary residence. Now that I think about it, why would I want the lowest end equipment in a rental too?

For rentals the argument goes that who cares what you have there? The electric bills are paid by the tenant. So because the rental is a for profit entity bean counters choose the less beans method. Lower end units are also cheaper to repair. The reason you don't want them for your personal residence? The line now is greatly blurred because these machines are just as quiet as a big name brand. Some may say they are less reliable, but if installed properly they aren't any less reliable than anything else.

If you're in an area with heavy use (not a mild climate) these entry machines are typically less efficient. But minimum efficiencies are getting ready to change too. 14 SEER will be no more as SEER will become SEER2 and roughly 70% of what is made now will be scrapped to meet the new SEER2 requirements. The benefit in this is higher efficient equipment, the other unintended consequence is confusion which will lead to misinformation or fake news if you prefer. LOL.

Payne units come out of the same factory probably not more than a few feet from Carrier/ Bryant The Payne brand along with a slew of other brands is more or less the same thing as entry Carrier or Bryant brands. In my area Payne brand is not available any more. Other brands take this spot: Grand Aire, Arco Aire, Comfort Maker, Heil and many more...

Why would a manufacturer do that? Things go bad for one brand name. People associate things with that name, say I will never do this or that again. They choose another brand that unbeknownst to many people is the made by same company well unless they go to another major brand like Trane, Lennox, Goodman etc. Brands don't matter all that much. I work on all of them, they all are common in that they all break. The more you use it, the more likely that happens outside of everything else like sizing, proper installation, duct work, maintenance, who is doing that maintenance, are they doing it properly and so on.

Anyway, the contractor today didn't see the point in a 2-stage. He was pushing variable speed like crazy and was saying you might as well go all (variable) or none (single speed) if you're going to do it. His reasoning for variable speed in a moderate climate is that you can operate the unit according to the temps outside, and if they're moderate the unit won't have to work as hard....

True. Variable speed compressor should be referred to as Inverter. While it's true that it is variable these terms tend to get mixed up with other terms referred to by variable speed blower and they just call that a variable speed unit. So it's important to know what it is you're referring to.

If load calculations are so important so should be how the system operates. An Inverter AC system have the ability to "match" the load. They continue to search for that load (whatever it is) so they keep running. Manfacturing methods can vary so some inverters aren't the same due to limitations a mfg may put on them.

Typicall an inverter is going to cut the usage of up to 50% of that of a 14 SEER rated machine of the same capacity. Even though the inverter will run longer than that 14 SEER machine.

If it's hot, the inverter knows because it is always search for that proper capacity level. These up and down performance levels result in 1% up / down differences in capacity. The con if there was one is that most major MFG's like Trane will require proprietary hardware to operate it as designed. If you at some day later in the future go back to traditional off the shelf hardware often called "legacy or analog" this will cripple the machine.

Bosch and Amana / Goodman MFG's do things different. Daikin same thing as Amana / Goodman - the electronics that run the inverter is in the furnace or air handler.

Bosch is different in that you can pair it with any traditional furnace or air handler. Just a regular 24 volt signal. This is partly why I'm more in the Bosch camp than the others because Goodman/ Amana years ago had communicating stats (proprietary) that are no longer made. You can revert back to legacy on those, but this essentially cripples the machine as to how it was originally intended.

In a two speed condenser capacity of machine is around 70% of the capacity of the over all machine. An inverter with 1% stepping up and down will run circles around that and if operating cost is a thing in your area --- depending on use you *could* easily recoup the difference of the cost from the inverter machine to the 2 stage.

I would say if you plan on keeping this house, the inverter might be? But a mild climate? Yeah that's a tough call to make. Because a lowly rental Payne unit / properly installed could work too. It greatly depends on what comfort means to you.

BTW: air handlers are 240v --- because you need 240v to run electric heat strips. The blower motor in those are also 240v. Gas furnaces are 120v.

Good info to learn about 240V for heat strips. I wonder if they'd be installed in this area of SoCal - I can't imagine overnight temps would ever much stray from the mid-40s, well within heatpump operating range. If it were me, I'd stick with a gas furnace.

Short cycles in gentle climate areas are very noticeable, especially for those who use overnight setbacks during heating season or when coming home on a hot day and the AC turns on.

"If load calculations are so important so should be how the system operates."

Quote without comment, it says enough as it is. "If" ? Load calculations are required in many circumstances and are good practice in most all others.

Wow, thanks Elmer and Austin - tons of great info. I'm kind of steering away from variable after doing comparisons on hvacopcost. It seems, very roughly per estimations there, that the difference in cost savings per year between a single and variable speed heat pump is somewhere to the tune of $400-600 depending on efficiency. If I were to upgrade from a 15 seer single speed Carrier unit it would cost me anywhere from $3100-4800 more (going to an 18seer 5-stage and 20seer Carrier Infinity). This translates to a 7-8 year break even period to recoup those costs! I can see how in a hotter climate this would make a ton of sense but it just doesn't add-up as much for me, personally, in the mild climate. So I'm having trouble understanding the other contractor's logic that variable speed units make just as much sense in moderate climates. He said he has argued this point a lot with people... hahaha - I'm just not seeing the reasoning as to why but his main point was that if you're in a milder climate your variable speed unit should, in theory, run more often at the lower available speeds and save you lots of money - sure, but at what up-front cost? He seems to forget about the ROI behind it... if we had solar then I guess none of this would be much of a talking point of course.

Regarding heat strips, I've also heard they're probably not necessary out where I am. Do systems installed without them still need to be operating on 240v then? In my case, this may not matter as I'm currently discussing this option with the one contractor who actually suggested a hybrid system as an option - I was looking into this even before meeting him, not for the normal use case of having gas kick in when the heat pump can't, but for the unorthodox reason that I can have the availability of TWO fuel sources in case one becomes unavailable OR I can choose one over the other based on current rates (e.g. use the gas furnace while NG is cheaper and once they start raising prices and/or we go solar, then cut over and use the heat pump for heating instead).

Also, this same contractor is highly confident I'll qualify for the $3k rebate despite other contractors telling me hybrid systems can't qualify (not sure if maybe they told me that because it's more work for them to setup a hybrid system vs straight heat pump system). I asked him to double-check on this - one contractor told me he had to show picture proof that all gas furnaces were removed and that none were installed... I trust this contractor though solely based on even suggesting the hybrid system as a viable option AND encouraging me to consider it for the rebate. He probably has the most years of experience out of all the other guys too...

So right now, I'm looking at a couple options:

Carrier Comfort Series 15 SEER 1-speed AC

Furnace – Ultra Low NOx 58SUOAO80E2120 80k Btus 80%AFUE with Multi-Speed ECM indoor fan

AC unit – 4-ton model 24AAA548 15 SEER with evaporator coil CNPVP4821

Price $11,991.00 Cash/check Price $11,392.00 AC sound 76dB

Upgrade AC unit to Performance 16 SEER model 24APB648 AC Sound 68dB Add $750

Carrier Performance Series 16 SEER 2-speed AC (recommended for zoning)

Furnace – Ultra Low NOx 58CUOAO80C2120 80k Btus 80%AFUE with Variable-Speed ECM indoor fan

AC unit – 4-ton model 24ACB748 16 SEER with evaporator coil CNPVP4821

Price $13,816.00 Cash/check Price $13,126.00 AC sound 72/74dB

Change to Heat Pump model AC to qualify for additional $3k rebate Add approx.$1,000

I'm considering going down to 3.5tons right now, just to have some 'buffer' above the suggested 3ton (e.g. primarily if we have family staying over with us multiple times, which we do plan on and have right now as my in-laws sometimes come in or those times where we might have people over and/or are hosting). He did give the option of moving down to 3ton which would reduce the cost by $500. I'm deliberating between single vs 2-speed and also efficiency... there's no 14 seer option that he gave at least for Carrier. I could ask him for his pricing on Bryant but he didn't seem as keen on this (probably because he prefers to sell the flagship name...but I think he probably would be open to it if I ask)

I think we've established that I'm better off leaving the furnace in the garage (rather than relocating to the attic and also bothering with zoning) but I'm wondering if we should also consider changing our ducting out as well or if it's best just to do that another time. He's charging $2300 for ducting, which seems reasonable.

What are your guys' thoughts on the built-in air purifiers/ionizers out there? He was offering the Carier Merv15 air purifier and also the iwave-r ionizer as add-on options.

Other details on the install and warranty:

Includes: Labor, materials, tax, Wi-Fi thermostat, bar type grilles, enlarge living room duct and grille

(eliminate other), seal and insulate garage ducts, insulated plenum sleeve, clean and seal platform

return, gas flex and shut off valve, furnace electric cord, drain overflow switch, polyurethane AC

equipment pad, new 220volt AC breaker and fused disconnect switch with new whip wiring, easy access

filter base & 1” MERV13 disposable filter, pressure test and flush Freon lines with detergent flush,

condensate drain lines to be flushed, remove and dispose of existing equipment and related debris. All

work to be performed according to local city codes and title 24 compliant. City permit, 3rd party HERS testing fees included. 1st year maintenance visits are free with WEB review

Excludes: Painting

Payment Schedule: 10% deposit, 50% upon equipment delivery, balance due day of completion

Warranty: 20-yrs heat exchanger (lifetime on variable furnace),10-yrs all equipment parts, 5-years labor,

lifetime workmanship

You went through most of the winter without a furnace, so I would think an 80K furnace is over sized. The 80K furnace was likely picked to match with the 4 ton AC. That also seems over sized. If you got the 2-stage AC it rarely need to operate in the second stage unless you had a large temperature set back.

What thermostat is being installed? I recommend installing a 4 inch media filter. Electronic air filters are not necessary and become maintenance problems in my opinion.

If you are keeping the gas furnace then you should not need electric heat strips. You might need them if you install the heat pump and if you plan to run the heat pump in temperatures below freezing.

Our current furnace is 88k. We definitely would have run it more if it worked haha. Are you a proponent of the 2-stage then in the sense that it would run presumably at the lower speed compared to full blast/single stage and therefore have a significant enough cost savings?

"temperatures below freezing."

I don't think that ever happens in the Laguna Hills area. I doubt the temps ever get lower than the low 40s and overnight winter lows are typically mid-40s and higher.

I'd stick with the basics that meet the specs and agree with an 80% furnace - the higher equipment cost and added installation issues to switch from an 80% furnace that I presume is there to one with higher efficiency will not likely be recovered in gas savings. Higher SEER values and the rest are probably also not worth the extra money. Ditto with filters, keep it simple. If you want to save money on energy, buy or lease solar panels.

Just to confuse the issue a bit, Bryant equipment is made by and has models identical to Carrier but can be a bit cheaper. Now that you have Carrier model numbers, see if you can get a quote for the same with a Bryant nameplate on it - it should be cheaper. Same HVAC contractor or find another.

PS - I'm glad to see the work is being proposed to include a permit and HERS testing.

Good luck.

Yea it doesnt get too crazy but i think there were a couple nights it reached into the 30s....

I did stumble across this btw: http://sagoro.wrightsoft.com/Carrier/Default.aspx

The contractor I'm talking with now says his pricing is the same between Carrier and Bryant so not sure if his discount on Carrier is *that* good or what. The downside going with anyone else is that they may not know how to setup the hybrid configuration and they certainly wouldn't know how to work the rebate in either. If I go hybrid gas/heatpump with this guy, it'll end up costing less than the standard gas/AC combo after the rebate is factored, so it kind of seems like a no-brainer to go hybrid and switch the gas furnace to aux/emergency mode and exclusively use it for heat when needed.

His attention to detail and things he was pointing out (like looking in the air return that passes under our stairs and calling out exposed insulation and spaces that he would seal up with duct board etc) are what has set him apart from all the other contractors at this point. And on top of that he saw all the fishing gear in my garage and it turns out he's an avid fisherman as well so we started trading stories lol... I dont want to creat bias in my decision but he honestly does sound like he knows what he's doing along with the how and why...

Are you thinking it will be cheaper to heat with a heat pump than with natural gas? I wasn't down there this past month so my usage wasn't over the baseline, but what I saw suggests that you'll be paying between 25 and 30 cents per kwh for electricity for the heat pump, versus just a but over $2 per therm for gas. I can't imagine the heat pump would be cheaper to produce heat but maybe you've calculated it?

Heating with heat pumps instead of gas furnaces may be California's future but the fact that heat pumps have been common in other parts of the US for decades (homes without natural gas. Or areas with cheap electricity, something you don't have with SDGE) and uncommon in California makes me wonder why you'd want to go that way. Mini split heat pumps have become less rare for additions and rooms with heating or cooling issues, yes. But full-on split heat pumps, not so much.

How long do you plan to own this home?

Only if we go solar, which I'm seriously leaning towards at the moment as we have to update our electrical panel anyway and the time/effort/cost involved with doing that would seem to warrant doing a complete overhaul of our electrical system and introducing solar. So this would be a way to 'ease' off of gas, if "necessary" or if the numbers call for it, and onto electrical/heat pump use or to at least provision for that. Electric costs in my area are 39 cents/summer and 49 cents/winter which is even more outrageous and would provide more justification as to why we would want to consider solar.

But yea, the nice thing at least per my understanding is that we can operate the heat pump strictly for cooling-only and use the gas furnace (in aux/emergency mode) for heating and not use the heat-pump to provide heat at all. In theory, this should get us the same net-effect cost as using a regular gas furnace/AC condenser system. And the upside is that I'll have paid $2000 less for the heat pump/gas hybrid combo than if I had gone with the standard AC//gas furnace to begin with.

We are hoping to be here long term but if the market crashes and there's opportunity to pick up another place, I wouldn't mind moving either if we can find a steal and rent this place lol. Half-joking on that one - we really like the location of the place now but you just never know. The intention of moving here was to make it our long-term primary though.

BTW: is there something inherent about heating pumps where they consume *more* electricity when cooling-only when compared to their AC counterparts? For example, I'm comparing the cooling cost of running the single stage Carrier Performance 16 (24APB642A00300) to the similar heat pump equivalents (25HBC542A00300, 25HPB642A0030, 25HCB648A00310) and the cost of operating the AC unit is lower than the heat pumps for *cooling* with the smallest margin being $72 - I would think it would be a lot closer... do heat pumps require more wattage to run in general?

If I were to upgrade from a 15 seer single speed Carrier unit it would cost me anywhere from $3100-4800 more (going to an 18seer 5-stage and 20seer Carrier Infinity). This translates to a 7-8 year break even period to recoup those costs!

Yeah it's going to take time to recoup it. If it were me though I would not choose Carrier inverter because they cripple it to only 5 stages. If you're spending that kind of money much better to have upwards of up to over 60 stages vs only 5. That said it's a choice. If you're staying put you should at least consider it. Mild climate with high electric costs? It's a borderline thing I think.

The difference from true inverter is 1% up and down increments, not 20% increments. Then there is the infamous hissing sounds the Carrier makes going into every off cycle. I doubt they include those noises in their literature.

The contractor I'm talking with now says his pricing is the same between Carrier and Bryant so not sure if his discount on Carrier is *that* good or what.

If this guy is a Carrier dealer, that is where his priorities are. It would be counter productive to sell Bryant. He's signed a committment letter to sell xxx number of Carrier systems typically layed out in dollar value per year. The more he sells, the more he buys of Carrier the better his prices become. If someone wanted to be a Bryant dealer same difference.

It's a money game vs volume game. But the volume game isn't significant from the unit here / unit there perspective. It's the overall picture and there are price increases that come regardless. Price is always moving, always changing. It's all about sales when it comes to these kinds of reindeer games.

Larger companies have been known to get into offering more than 1 brand. Because they have the volume of sales to do so. Which typically puts them in a sell, sell, sell type operation. Nothing wrong with that in and of itself unless you start hoodwinking people to sell, sell, sell. In a world of banned / phased out refrigerants -- this probably won't matter as much as it used to. Time for you to buy something. LOL. I tell it like it is, maybe you see the humor it like I do.

BTW: is there something inherent about heating pumps where they consume *more* electricity when cooling-only when compared to their AC counterparts? For example, I'm comparing the cooling cost of running the single stage Carrier Performance 16 (24APB642A00300) to the similar heat pump equivalents (25HBC542A00300, 25HPB642A0030, 25HCB648A00310) and the cost of operating the AC unit is lower than the heat pumps for *cooling* with the smallest margin being $72 - I would think it would be a lot closer... do heat pumps require more wattage to run in general?

So I am assuming that you've been using this operational cost estimating tool? If that's the case I provide some examples below why operational estimation costs can be *tricky* for the lack of a better word. This is also another reason how people get duped into thinking they are buying xx efficiency when in fact due to configuration --- they are not. To be clear configuration means the whole ball of wax here. Equipment selection, line set sizing, ducting, proper charged refrigerant and so on. Everything that makes up the HVAC system can have an effect on efficiency good or bad either one.

click to enlarge.

The first two you can see the same condenser used but differing AH's the result is 14 SEER for one and 17 SEER for the other. You can see similar performance using that same AH for the heat pump split higher efficiency HP. But when it comes to HP's you also have to look at the performance in heat mode. A bigger number there is better performance of which I underlined in the picture above. Also note this example is 3600 BTU cooling or 3 tons AC.

Now what happens when the only change you make is equipment sizing? The jump to 4 tons of AC? click to enlarge picture.

This is essentially why they tell you to buy a "matched" system. But they never tell you to pay close attention to what it is you are "MATCHING". Notice that the heat pumps in this configuration are essentially identical? what kind of trickery is going on here? lol.

Just realize this is merely an operating cost ESTIMATE. Your mileage will vary. That said you have to rely on the skill of those you have chosen to do this.

Also note: These configs in the pictures I show above are configured with an ELECTRIC AH / not gas duel fuel combo. Keep that in mind. You change the config good as well as bad things can happen.

If anything this demonstrates what? you get what you pay for more or less. Just because it's a fancy dancy condenser doesn't always mean it will deliver the goods. This is also another reason the MFG will not take a hit because these estimates don't pan out to what you think they will. Read the warranty fine print. Use a skilled contractor.

If you're seeing disparities -- raise those questions to your HVAC contractor.

The 18 SEER Carrier Inverter only has 5 stages but I think the Infinity 24/26 with the "Greenspeed" is the one that has a ton more and is truly variable

"Greenspeed intelligence is created by pairing adaptable-speed technology with the Infinity® System Control. The unique, variable-speed compressor of this unit, allows it to literally adapt its output to the needs of the home. With tiny adjustments between 25 and 100% capacity, it gives the home only the amount of cooling or heating necessary."

This is the one that costs $4800 more... practically, besides the cost savings of the HVAC system, I don't know what this actually translates to while we're sitting inside of our home and it's cooling or heating. Everyone keeps talking about "comfort" but what does that mean to me and my limited experience/knowledge of AC systems? Haha

Like, if I spend that money to improve the insulation of our home and "make a super tight envelope" would a variable speed system still be something we would want? Or would a single speed system make even more sense at that point? Right now, and I think I mentioned this already, but based on our limited time being here so far it *seems* as though the house tends to cool down or stay cool a lot easier than it does heat up. I think part of this is that we just don't get as much sun hitting the sides of the house and the windows are double-pane if it does. I think the Spanish clay tile roofing is deflecting a significant amount of heat on top of that. Everyone cares about cooling more than heating in this area, generally speaking. But I feel like to us heating has been more important than cooling lately!!! Right now, 9:20am PST it's 57F outside. Downstairs temp on thermostat reads 62F and upstairs it's reading 60F on my AQ monitor :T

I had never heard of those hissing sounds. Is that just the way the system works? Or is that something that can be addressed by the installer (or is caused because of installation not done 100% correctly)?

Regarding relocating and zoning, it seems like, ideally, you'd want the attic to be at least cleaned up, sealed off and insulated from the outside before considering putting anything up there. I guess in a situation where we had funny money to throw out the window, we could do all that and transform our attic into a conditioned space or at least finish it the install the highest end variable speed system + zoning and really have the most top of the line house on the block lol. One can dream hahaha.... EDIT: actually, doing all of the above minus insulation/finishing/conditioning the attic would cost just over $21k if we went the Infinity 24 route hahaha. I'm guessing improving the insulation would range anywhere from $3000-5000 depending on if we do blown-in on top of what we have vs removing all existing and placing new R38 in. It sounds like not as great an idea though with the potential temp extremes in the attic and strain it could cause on equipment that's operating up there. I think I read that some contractors actually push doing this because it makes their job easier in terms of reworking ducts, etc... I guess because pretty much *everything* is up there at that point.

As it is, we just want something that will cool and heat the house as needed and will last us a long time. The single speed vs two-speed vs variable speed just makes it a lot harder to choose at this point. I'd be open to the Bosch unit but I like the idea of a hybrid setup right now (I seriously doubt the Carrier contractor I'm leaning towards would install a Bosch unit lol) and I just don't believe the other guy when he says our electric bills won't go up that much and will be less than if we had stayed on gas (he was pretty much saying/implying this). HVACOPCost and the Carrier OPCost calc both don't agree with that at all... that guy must not be familiar with SDGE rates either LOL. Ideally, it would be awesome to be able to put the Bosch HP in with a gas furnace and get all the rebates then just operate the system in AC/gas furnace mode until we go solar... actually, looking at pricing again the Carrier Infinity 24 Greenspeed HP/gas furnace combo *I think* would cost us less than the Bosch HP the other contractor was suggesting when factoring in the $3k rebate. This would put it at just over $14k if my math is correct. This doesn't include ducting and is strictly for the component install btw. The Bosch HP cost to install is over $15k... I would be curious about the direct comparison on the Bosch (BOVB18) and the Carrier Infinity 24 w/ Greenspeed.

It's just my opinion from your comments but I think you're waaay overanalyzing your needs.

I'll appreciate comments from those with more familiarity than I have, but I'd thought the Greenspeed products were for places with more extreme weather, both colder winters and/or hotter/more humid summers. Your location is or is adjacent to the mildest weather region in the US. You don't need a Ferrari to drive your kids to school. The occasional and light HVAC usage that's typical where you are doesn't require high performance capabilities, in my view.

To put your pricing in context, and I know both supply/demand factors have changed and my equipment is slightly smaller, but a bit less than three years ago I paid $8300 to a busy and highly rated contractor for the new gas furnace, new coil and new outdoor AC unit, all Bryant equipment in their middle (not bottom) series. My place is about 40 minutes south of where you are. The work also included ducting and cutting in an additional vent in an upstairs room, and putting in more adjustable supply grills. At the time, I had bids ranging from $7400 (for no-name equipment) to $9500.

PS - I've heard that heat pumps don't last as long as AC units. AC is used during hot weather, a heat pump config is used then and also for heating in the winter time, so more months of usage per year. Another opportunity for those with more familiarity to share what they know.

This is the one that costs $4800 more... practically, besides the cost savings of the HVAC system, I don't know what this actually translates to while we're sitting inside of our home and it's cooling or heating. Everyone keeps talking about "comfort" but what does that mean to me and my limited experience/knowledge of AC systems? Haha

yeah it's a tough call. Really for a mild climate like yours it's more about operating costs & having the best. Why is it the best?

1% up and down ramping. Your house is a heat magnet when the flaming ball is in the sky over head. How much heat does he propel your way at 9am. 12pm. 3pm. 4pm etc. It changes all the time. Electricity. if your system is ramping up and down between 25% to 40% to maximize and deliver proper cooling depending on where the sun is and how much heat it's propeling to your magnet. You can insulate it, seal it but put in an oven over time it gets toasty inside.

If your system is either on or off? one speed. There's a call for cool at 9 am. it blasts some cool for 10 min shuts off. Because the cycle was so short it never even achieved it's most efficient state. Maybe 15 later it cycles again and the process repeats. Between 3-7pm in the summer months is typically the only time your AC will likely hit those 30-40 min cycles. If over sized due to climate change? probably 20 min cycles best case scenario.

If it pays you back in 7 years? It paid you to have the "best". -- assuming it is a fully inverter variable AC.

I had never heard of those hissing sounds. Is that just the way the system works? Yeah, normal operation. That is how this particular unit is designed to operate. You never heard of it, because they (the MFG of choice) are trying to sell you. No one is going to print the bad about anything. They wouldn't sell any if they did that.

Ideally, it would be awesome to be able to put the Bosch HP in with a gas furnace and get all the rebates then just operate the system in AC/gas furnace mode until we go solar...

Yeah the rebate is almost certain not going to allow that. The Carrier dealer is probably carrier only. Due to pandemic we've been cut off at the knees. If you're not selling enough to be considered a "dealer" for any brand, you will simply be told there is none available. Nothing personal, just business. (Seriously that is what I was told, I spoke with the high ups not just someone behind a counter at the distributor.)

There are still shortages to this day. But I've been able to work around those issues. Thankfully I have used 7-8 different brands over the course of owning my own company so I am not afraid to go there again.

My view is the Bosch is the better made product. Is it perfect? No, but there isn't anything else that's perfect either. So it's all relative, they all have supply issues. While some of these are assembled here, you can't assemble them without labor nor without parts that are made in other parts of the world. Bosch currently is only made in China -- they say currently that product is on ships and shortage should be relieved soon.

So to this day, I say if you want something and can find it... you better do so before someone else takes it. Much easier to find a plain jane entry level AC. So if you're in that boat the name on the side of the unit might be your only concern. What's in a name?

I fix all of them, they all break. I haven't found a brand that never breaks.

For sure it makes for a difficult decision. What makes it harder is not knowing how our house handles the heat of the summer here. But let's assume it does and stays cool or tolerable inside even during the hottest of days. There may be little to no need to run the AC. So even if we have a variable speed AC (which I suppose I might liken to a luxury car that gets ridiculously good mileage), it's kind of like paying a lot more for a car with crazy high MPGs and using it only once or twice a week, when most people would buy cars like this intending to drive them as a daily commuter.

So in that sense, is the cost savings worth it compared to the lower cost single-speed AC (the lower cost entry level sedan that doesn't get great mileage but is decent) that I'm using for the same purpose? I don't know... I guess it depends on the cost differential. But I think missing from the equation here is how hot it *actually* gets inside of our home to justify spending more on something that seems to make more sense running frequently/all the time. I guess there are multiple ways to look at this (half glass empty or half glass full) but I'm trying to look at it in the big picture sense: upfront cost + cost of operation + cost of maintenance. It *seems* that single makes more sense in my situation and especially if we live in a house that tends to stay cooler than it does hotter (of course, I don't want to assume that incorrectly haha). I get the piece about not going full-blast for 10 minutes at a time and short-cycling though.

So in this case is a 2-speed system actually a good 'compromise'? Obviously we've discussed the whole "go big or go home" mentality with doing single or variable... or is there really no good "in-between" solution here? I've also heard of single-speed units paired with an ECM blower. Someone over at HVAC-talk briefly mentioned this:

"The only negative difference with VS motors is they are very expensive to replace, as much as 3x more than a multi-speed blower. If you are thinking of a single-stage system, but you want some of the benefits of a VS motor, a ECM or constant-torque motor is a good in between. It doesn’t have the programming, but it doesn’t come on jarringly, maintains airflow, and usually gives a slight efficiency bump over multi-speed motors."

I was under the impression that ECM and Variable Speed are one in the same though?

Anyway, if that were a good viable in-between, then perhaps I can consider pairing these two:

https://www.carrier.com/residential/en/us/products/heat-pumps/25hbc5/

https://www.carrier.com/residential/en/us/products/furnaces/58cu0/

Of course, I just ran a comparison and it seems single speed SU0 furnaces supposedly cost less to operate than the CU0 furnaces, which is surprising to see... but per what you said earlier, Austin, these are just estimates. So I guess, in theory, the CU0 *should* cost less to operate even with a single speed heat pump or AC unit?:

I realize the total annual cost numbers are likely skewed because this calc assumes usage of the way a hybrid split was *intended* to work (only use gas in extreme temps and cutover to heat pump in the more 'normal' temps). But I'm guessing that if we configure the system to exclusively use the gas furnace for heating (via aux/emergency mode) then the numbers should pretty much be the same across the board.

It's tempting but I don't want to ask the Carrier guy if he'd be open to installing the Bosch as I've already asked him a lot of questions (and he has been patient) out of fear of him getting pissed or dropping me all together because it just looks like I'm tire-kicking at that point lol.

BTW Austin, what are your thoughts on zoning and relocating to the attic? Bad idea in general if we're already in the garage (which is slightly insulated but not conditioned). The attic can get hot, and zoning seems like overkill in our situation too. Right now, it seems keeping the system where it is is the way to go.

BTW: I was looking at the comparison directly between the 58CU0 and 58SU0 and get this:

58CU0 is the Infinity line where 58SU0 is the Comfort...! The numbers make no sense - did they mix those up or something? How is it that the 58SU0 ends up costing *less* than the 58CU0? I even paired these with like-kind HPs and condensers and the heating cost is consistently higher on the 58CU0 than on the 58SU0. I mean, this probably goes back to what you were talking about earlier too...

Right now, I'm thinking about pairing these two units for 3.5ton sizing:

25HPB642A0030 & 58CU0A080C21--20

--contractor says we'd have to upgrade the coil type to take advantage of higher SEER - right now it seems 58SU0 and 58CU0 is the same and gets you 15seer out of the box. It seems like the variable speed motor blow/ECM doesn't provide much more benefit than the multi-stage at that point, is $600 more and questionable as far as if it'll even fit with the vertical stack space in our garage.

Yeah I think you are on the right track understand the pro vs con like the analogy of the ICE car vs the EV. The estimate on costs is more or less there for you to come to some decision. I think the estimate will be pretty close to reality. But these kinds of things will fluctuate, just as much as the cost you pay for electric and or gas.

Obviously if you go the heat pump route, you could spend more money for solar and then have the luxury of low or no utility bills. You can't do that with gas. But how many years will it take you to recoup that? You many never see the end of it.

The difference from ECM to Variable Speed to multi speed PSC --- it's cheaper to run / operate the ECM or Variable speed but the cost to replace can be very expensive and in the current state of this world you may not find a replacement ECM or Variable Speed motor. They have chips in them. The PSC doesn't have those concerns.

It's costly to convert a gas furnace ECM or Variable Speed motor. It's also costly to replace the ECM or Variable Speed. In terms of operation ECM and variable speed are similar. For a mild climate? you could argue both ways.

So why? to hit efficiency numbers the government puts into law as a minimum requirement. It's partly the Federal Government that does this along with local governments.

The numbers that estimate spits out is likely a tested configuration. The SEER rating that is given for each combo tells the story. The higher the SEER rating (of the configuration) the better or cheaper the operational costs will be given what you pay for electric / or gas in a given area. The HSPF

So here's some more comparisons I've paired some higher up machines, I know they are higher up only because of SEER ratings and HSPF performance. But due to your high electric rate you pay more for heat pump than you would gas heat only. Heat pump operational costs would bring these numbers down if you had solar. So you spend even more money for that.

In terms of the *Infinity* line... it's more about advertising. There are a myriad of combos to get to various efficiency levels. Some pairings can not be achieved... if you take the units I show in the picture and try to match them differently you will see what you can and can't pair them with - so just the word *infinity* next to something in the Carrier line up doesn't tell the whole story.

That 25VNA4 is a high up, they limit what you can match that with indoor. You can't match that with the very close 25VNA0 Notice between these first two HP performance is very good considering the others. So in areas where heating is more the concern you choose the 2nd one as opposed to the first one.

But the costs for heat are nearly identical. --- for you that operating cost is higher than natural gas.

In a mild climate like yours that 21 SEER on AC side for the first one or 3rd choice notice the drop of 1 seer for ac and 1 HSPF with just a different furnace selection.

Hopefully this provides more clarity. Probably not but worth a shot.

Thanks for the info. Very useful. In terms of heat pump vs gas, this is why I was considering the hybrid heat. Solar is still on the table and though I do want it, it may not be something that comes to fruition right away and for a few years I'm guessing. Unless I'm really desperate for that tax credit and don't want to miss out (which is a good reason not to drag my feet). But in the case that we do get solar, I figure I can just fully use the heat pump for heating (and set the threshold for the gas cutover to be absurdly low, however you would do this) and have solar fully pay for or at least heavily subsidize our heating costs.

So actually, I was looking at the specs again and the 58SU0 has a multi-speed ECM... the only furnace options I have are those (that have the ECM motors) too so I don't really have much of a choice there. I'm assuming multi-stage ECMs are still a lower cost than the variable speed ECMs though.

For me to move from 15seer to 16seer (and going down to 3.5ton from 4ton), according to the back and forth pricing I'd be looking at $12900 I think (Cost of the original AC/gas 15 seer base combo was $11991). This doesn't include the $3k rebate which will bring us down to $9900 for this combo (he was saying he'd still need to change the coil to CAP to get 16seer):

If your plan is to add solar, then running in heat pump mode for heating and your operating costs could go to near nothing depending on a few variables. Like if the solar is grid tied requiring utility hook up.

I think the more and more people choose solar, there's going to be a reckoning day where grid tied solar solutions start paying for the grid connections in other ways.

There's the idea that utility companies are going to keep maintaining the grid, producing power only to provide supply when the sun isn't shining. I suppose you then go out and buy a power wall or something to fully free yourself from grid tied power. So I don't know that it will end completely by even just adding in solar only.

Due to electric costs without solar it would be pointless to heat with the heat pump. Gas heat would rule the day. If you get the rebate and spend it on power consumption by running the heat pump it doesn't make sense to do that.

If you do the hybrid heat pump + gas, run gas heat until you get solar -- then you avoid those high energy costs of actually using the heat pump.

PSC vs ECM vs Variable Speed ECM --- the argument is mostly about efficiency, but when talking about efficiency as related to these motors --- the cost of replacing ECM or Variable Speed ECM will render any efficiency gains (what you spend operating them) obsolete. The amount you save running them will never equal what it costs to replace them when they wear out.

PSC the argument is this motor is louder and less efficient. But these motors tend to last much longer and cost less to replace. They will argue that this motor needs a capacitor to operate while the others of the ECM variety do not --- which is not completely true. The capacitors of the ECM either rendition are internal to the motor. When those capacitors fail you replace the motor or a module that attaches to the motor in the case of the Variable Speed ECM.

I have found that it's not wise in my climate to only change a module or a motor that attaches to a module when it comes to the variable speed ECM --- the cheaper ECM there is no module even if there was it wouldn't change much.

So why an ECM or Variable Speed then: efficiency requirements. When you buy a completely new system the efficiency of the furnace / AH paired with your AC or HP condenser will help your manufacturer hit those higher SEER, HSPF and AFUE Ratings.

But when considering these things the savings you get from the motor in operational efficiency will never = the cost of replacing this motor.

The variable speed motor (ECM) is the most efficient of these three motors and also the most expensive.

That said the gain these furnaces / AH's typically provide is about 1 SEER of efficiency toward the over all efficiency of the system.

Yes E-coil selection as well as configuration of that coil (upflow, downflow, Horrizontal) can impact efficiency ratings positively as well as negatively. -- usually this disparity is minor in the grand scheme of things. But when trying to get a rebate for something specific and you don't pay attention to detail -- they will tell you don't qualify for the rebate if what you do doesn't measure up.

The whole solar/grid infrastructure relationship is an unsettled area. The problem is that until home power storage becomes more robust and affordable, homes with solar panels need grid connections to bank excess production or to provide power when panels aren't sufficient for needs. Electrical utilities have become distribution only businesses - their revenue for grid building and maintenance is included in the per unit electricity delivery charge. A solar powered home needs and uses the grid but doesn't wind up paying its fair share.

Changes have been proposed in my state to 1) reduce the amounts paid to solar customers for excess production fed upstream (backward movement of meters) and 2) to charge them a monthly fee for grid support. The amount proposed would be a fee of about $50/month for an average size home solar install. Given that average electricity bills for houses (not apartments, condos, or businesses) can be at or above $150/month, especially in hot areas using a lot of AC, this is not an excessive charge.

jplee3, call neighbors you know and take a walk around your neighborhood this Saturday and ask how many homes without solar panels have standard full split (not mini-split) heat pumps for heating. I think I know what you will learn and you should think about why that may be.

Also, despite the obvious advantages in California, while solar panels on rooftops are often seen, it's still a small percentage of homes that have them. Maybe less than 10%, even in upscale neighborhoods. There are a lot of reasons pro and con that go beyond reducing monthly bills.

Heh, I'm guessing the answer is that they mostly don't have HPs installed and probably because SDGE is horrible and Natural Gas is way cheaper (despite all the contractors pushing HPs constantly asking "well, did you look at your gas bill recently?" hahaha). The NEM initiatives are making solar less favorable as time goes on (look at Florida), but the fact that you are grandfathered in for the next 20 or so odd years at the current NEM level + Federal tax credit/refund definitely makes it more appealing to install solar sooner than later. In most cases, it seems the ROI is somewhere between 5-10 years. In my neighborhood, quite a few neighbors have put solar panels on top of their roofs. I still cringe at the idea of doing that on clay tile. And the whole comp-out inlay method really concerns me too. But if you can find a reputable company who has many years of experience both in roofing and solar panel installs, it seems like that might be the way to do it if we were to. I'm in the process of researching it and contacted a few different companies to figure things out. I'm leaning towards putting panels up on our roof at the moment though.

BTW @mark_home, you mentioned 4" media filters - I looked it up and this guy seems not to be such a huge fan haha https://www.youtube.com/watch?v=K5OleOCcTew - he says in his description that they don't carry these at HomeDepot, etc but I just looked and see a bunch: https://www.homedepot.com/b/Heating-Venting-Cooling-Air-Filters/4/N-5yc1vZc4kwZ1z19a3b

Are 4" filters a relatively newer thing? And are they supposed to last 4x as long as the 1" ones or something? I'm used to dealing with 1" filters.

My parents have had a 4" (x20x25) filter module on their system for probably 15 years if not a bit longer. It's part of the air handler in the attic and is changed yearly-ish, easy to DIY except they can no longer get up there at their ages. Their replacement filters are not packaged compressed and do not need assembly, that's something specific to the choice of the fellow in the video. They continue to place a regular 1" (x20x30) filter at the return grill, changed on a "regular" schedule. The 4" filter is extra which keeps the evaporator long-term cleaner.

My 17+yo system was changed two months ago. I had a 4" filter added to the attic air handler, and will also continue to use 1" filters (20x25) at the two return grills.

A friend recently bought a 1970s remodeled house and found that the system there has only a 4" filter in the attic air handler, nothing at the return grill.

The 4 inch media filter is not new. They last much long than a 1 inch filter and lower air resistance. My filters usually last 12 months between changes. You can buy them on Amazon and other places on line.

Thanks for clarifying with the 4" - I asked about this and it's a $300 upcharge to add that to the system :T

I'll probably end up doing it. Supposedly the MERV15 Air Purifier was a free promo that ended so I missed out on that :( Not even sure if it would have fit anyway.

My understanding is that contractors have rebates thrown at them with no expiration given so the manufacturer will drop or pull them with the snap of a finger.

BTW: the quote he gave me for a single stage hybrid combo @ 16 seer is slightly less now than a 2-stage hybrid combo w/ the same efficiency rating I think. At that point, I might as well just go 2-stage! lol

Slightly off-topic question but do you guys think attic cleaning and re-insulation is worth it? Currently we have older yellow R19 batts up there and older ductwork. We were already considering re-doing the ducts (also dependent on what the load calc comes back saying with sizing). I had an attic cleaning/restoration company come out to take a look and they quoted me over $12k to clean the attic up/remove old batts, rodent-proof it (the guy keeps saying we have rats up there but I haven't heard any... I might put a few cams up there though just to see now that he has called it out), and then blow in new R-38 insulation. He even offered to add roughly 100sq ft of storage space (plywood planks) 'for free' if we commit to going with him and begin the process on Monday (talk about high pressure). That seems like a lot of money. It's 1700sq ft up there supposedly, and $3/sq ft for the cleanup and then $3.50/sq ft to blow in the new insulation.

jplee3 - Glad to see you here from that financial forum where I (under a different username) was pushing houzz pretty hard. Looks like you’ve got some solid input.

Good luck!